Light-emitting diode (LED) technology provides a lighting means that consumes less energy and is more physically robust, smaller, faster-switching, and longer lasting than previous lighting elements. However, the size, functionality, and configuration of conventional LEDs have constrained the use of LEDs to particular applications. One such application is the use of LEDs for backlighting devices.
In an apparatus having backlighting, it may be desirable to adjust the appearance of the backlighting to be compatible with different lighting scenarios in the environment external to the apparatus. This adjustment of the appearance of the backlighting refers to the color temperature of the light. With respect to the use of LEDs, since LEDs emit light primarily by processes other than thermal radiation, the emitted radiation does not follow the form of a black-body spectrum. As such, LEDs are assigned a correlated color temperature (CCT). CCT is the color temperature of a black-body radiator, which, to human color perception, most closely matches the light from the lamp. Currently, CCT dimming for LED technology is regarded as a difficult task, since binning, age and temperature drift effects of LEDs change the actual color value output. Thus, feedback loop systems are used (for example with color sensors) to actively monitor and control the color output of multiple color mixing LEDs.